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Shiga-toxin-producing Escherichia coli (STEC) infections usually cause haemolytic uraemic syndrome (HUS) equally in male and female children. This study investigated the localization of globotriaosylceramide (Gb3) in human brain and kidney tissues removed from forensic autopsy cases in Japan. A fatal case was used as a positive control in an outbreak of diarrhoeal disease caused by STEC O157:H7 in a kindergarten in Urawa in 1990. Positive immunodetection of Gb3 was significantly more frequent in female than in male distal and collecting renal tubules. To correlate this finding with a clinical outcome, a retrospective analysis of the predictors of renal failure in the 162 patients of two outbreaks in Japan was performed: one in Tochigi in 2002 and the other in Kagawa Prefecture in 2005. This study concludes renal failure, including HUS, was significantly associated with female sex, and the odds ratio was 4·06 compared to male patients in the two outbreaks. From 2006 to 2009 in Japan, the risk factor of HUS associated with STEC infection was analysed. The number of males and females and the proportion of females who developed HUS were calculated by age and year from 2006 to 2009. In 2006, 2007 and 2009 in adults aged >20 years, adult women were significantly more at risk of developing HUS in Japan.
Highly transparent conductive Ga-doped ZnO (GZO) films are one of the promising transparent conductive oxide (TCO) films for use in electrodes of flat display panels and window layers of thin film solar cells. For the ZnO-based TCO films, the stability to damp-heat environment is a crucial issue for practical applications. We will report moisture resistant GZO codoped with indium films (GZO:In) on the basis of analysis of data obtained a damp-heat test for solar cells (85°C and 85% relative humidity for 1000 hours).
We used ZnO sintered targets with contents of 3 wt% Ga2O3 and 0.25 wt% In2O3 to grow GZO:In films in ion plating with direct current arc-discharge system. GZO:In films with different thicknesses (0.1-1 μm) were deposited on glass substrates at 200°C under the O2 flow rate of 15 sccm. As the film thickness increased from 0.1 to 1 μm, the resistivity and sheet resistance decreased from 4.3 μΩm to 2.6 μΩm and from 42.7 Ω/Sq. to 2.6 Ω/Sq., respectively. And the average optical transmittance (Tav) in the range from 0.4 to 1 μm decreased from ∼ 86% to ∼ 75%. The GZO:In film with a thickness of ∼300 nm had a low sheet resistance of 10.5 Ω/Sq. and a Tav of 82.5%. After 1000 hours damp-heat (DH) test under 85°C and 85% relative humidity, the relative change of sheet resistance is 3.4% with a Hall mobility of 26.4 cm2/V.s and a Tav of 82.7% after test. The film thicker than 300 nm has a sheet resistance lower than 10 Ω/Sq. and a relative change of resistance of ∼3% after DH test.
Let G be a simple, compact Lie group and let be the gauge group of the principal G-bundle over S4 with second Chern class k. McGibbon classified the groups G that are homotopy commutative when localized at a prime p. We show that in many cases the homotopy commutativity of G, or its failure, determines that of .
The charge collection efficiency of a diode with a retrograde well was estimated using focused ion beam irradiation at 400 keV and 2 MeV. The retrograde well was found to effectively suppress a collection of charge carriers created by energetic particles. The charge collection efficiency of the diode with the retrograde well was ~ 25 % lower than that with the conventional well when 400 keV ~ 2 MeV protons were irradiated normal to diodes. This result was in good agreement with device simulation.
Application of negative heavy ions, alleviating surface charging on insulators, enables us to conduct low-energy and high-flux implantation, and leads to a well-defined tool to fabricate near-surface nanostructures. Negative Cu ions of 60 keV, at high doses, have generated nanocrystals in amorphous(a-)SiO2 with a size (∼10 nm) suitable for nonlinear optical devices. The kinetic processes, inside the solid and at the surface, are studied by cross-sectional TEM and tapping AFM, respectively. In a-SiO2, nanoparticles spontaneously grow with dose rate, being controlled by the surface tension and radiation-induced diffusion. Furthermore, the nanospheres give rise to a two-dimensional (2D) arrangement around a given dose rate. The 2D-distribution occurs in coincidence with enhanced sputtering where a considerable Cu fraction sublimates from the surface. The dose-rate dependence of nanoparticles indicates that the surface-sputtering process influences the intra-solid process and contributes to the 2D-distribution. A self-assembling mechanism for 2D-arrangement of nanospheres is discussed taking into account contribution of the surface sputtering.
We investigated the aluminum wiring reliability of fluorinated amorphous carbon (a-C:F) interlayer dielectrics (ILD) using electromigration tests at the wafer level under accelerated stress conditions with current density ranging from 25–32 MA/cm2 and a the substrate temperature of 300 K. The a-C:F film is one of the low-k organic materials with a dielectric constant of 2.5. The thermal conductivity of the a-C:F film (0.108 W/m·K) is about one order lower than that of SiO2 (1.2 W/m.K). We found that joule heating effect is enhanced by the lower thermal conductivity of a-C:F and that the wiring lifetime for a-C:F ILD is about one order lower than that for SiO2 ILD under high current stress. However, when the wiring lifetime is plotted as a function of the wiring temperature, the wiring lifetimes for both a-C:F ILD and SiO2 ILD became almost the same. The degradation of the wiring lifetime for a-C:F ILD is explained by the increase of the wiring temperature which is caused from joule heating. Moreover, the activation energy of the electromigration for a-C:F ILD has the same value as that of SiO2 LD at a temperature.
The technologies utilizing Fluorinated Silicon Oxide (FSG, k=3.6) and Hydrogen Silsesquioxane (HSQ, k=3.0) have been established for 0.25-μm and 0.18-μm generation ULSIs. However, low-k materials for the next generation ULSIs, which have a dielectric constant of less than 3.0, have not become mature yet. In this paper, we review process integration issues in applying FSG and HSQ, and describe integration results and device performance using Fluorinated Amorphous Carbon (a-C:F, k=2.5) as one of the promising low-k materials for the next generation ULSIs.
A new material for structures in space, which have a high energy absorbability has been developed using a powder particle assembling technique. Powder particles of polystyrene coated with nickel-phosphorus alloy layers using electroless plating were sintered at high temperature. A metallic closed cellular material containing polystyrene was then constructed.
The mechanical and ultrasonic properties of this material were measured at both room and high temperatures. The compressive tests of this material show a low Young's modulus and high energy absorption. Ultrasonic measurement shows that the attenuation coefficient of this cellular material is very large and would change due to increasing temperature. These results indicate that this metallic closed cellular material can be used for the space applications.
Nanoparticles of Cu were fabricated by negative-ion implantation, leading to spontaneous formation at high beam fluxes. Negative ions, alleviating surface charging, exhibit significant merits in carrying out low-energy implantation at high dose rates. The kinetic processes were studied by measuring dose-rate dependence of colloid formation and resultant optical properties. Negative-Cu ions of 60 keV were implanted into silica glasses at high-current densities, up to 260 μA/cm2, fixing the total dose at 3.0 × 1016 ions/cm2. Spherical nanocrystals of Cu atoms formed within a narrow region, near the projectile range of Cu ions. Simultaneously, much smaller particles spread out beyond a depleted zone, deeper than the projectile range. The nanocrystal growth and optical properties were greatly dependent on the dose rate and the specimen boundary condition. The growth process is explained by a droplet-model based on surface tension and radiation-induced diffusion. Beam-surface interactions also play an important role in the mass transport from the beam flux to the interior solid.
Deep centers related to proton-induced defects and impurities in n-Si were investigated using an in-situ DLTS system. The measurement system was installed in the beamline of NRIM cyclotron. Floating zone (FZ) or Czochralski (CZ) Si was irradiated at a flux of about 30 nA/cm2. The total dose was varied between 1.0 ∼ 7.2 × 1013 ions/cm2. Samples were irradiated at 200 K or 300 K. Their defect concentrations were determined by in-situ DLTS. Quantitative relationship between oxygen and phosphorus concentration and defect creation rates were presented. Isothermal annealing at 250 K was conducted for a CZ-Si sample and the resuflt indicated the meta-stable nature of the carbon defect complex.
We prepared 50 periodic nano-layers of SiO2/AgxSiO2(1-x). The deposited multi-layer films have a periodic structure consisting of alternating layers where each layer is between 1-10 nm thick. The purpose of this research is to generate nanolayers of nanocrystals of Ag with SiO2 as host and as buffer layer using a combination of co-deposition and MeV ion bombardment taking advantage of the electronics energy deposited in the MeV ion track due to ionization in order to nucleate nanoclusters. Our previous work showed that these nanoclusters have crystallinity similar to the bulk material. Nanocrystals of Ag in silica produce an optical absorption band at about 420 nm. Due to the interaction of nanocrystals between sequential nanolayers there is widening of the absorption band. The electrical and thermal properties of the layered structures were studied before and after 5 MeV Si ions bombardment at various fluences to form nanocrystals in layers of SiO2 containing few percent of Ag. Rutherford Backscattering Spectrometry (RBS) was used to monitor the stoichiometry before and after MeV bombardments.
This work is focused on nanoscale gold particle formation by low-energy ion irradiation in glow-discharge plasma and studying particle growth by increasing time of exposure.
SiO2+Au films on SiO2 substrates produced by ion beam assisted deposition (IBAD) were exposed to ion irradiation at 1.2 keV energy for 1-2 hours. Plasmon resonance appearance caused by nanoparticle formation was observed by Optical Absorption Spectrometry (OAS).
Thermoelectric power generation is a promising technology for increasing the efficiency of electrical and optical electrical devices. We prepared samples by Electron Beam evaporating Zn4Sb3 and CeFe2Co2Sb12 thin films on silicon dioxide (silica) substrates. The materials were co-evaporated and then were prepared for gold over-coating. Following electron deposition we performed post ion bombardment at a constant energy of 5 MeV while varying fluence from 1×1012, 1×1013, 1×1014, 1×1015 ions/cm2, respectfully. The production of nano-clusters generated from the MeV Si ions bombardment modifies the electrical and phonon interactions in the materials. Also, we will report on the fluence dependence of the figure of merit, Seebeck Coefficient, thermal conductivity and electrical conductivity. In addition, Rutherford backscattering spectrometry (RBS) was used to analyze the elemental composition and the thickness of the deposited material.
We prepared 8 periodic nano-layers of SiO2/SiO2+Zn4Sb3. The deposited multi-layer films have a periodic structure consisting of alternating layers where each layer is between 1-10 nm thick. The purpose of this research is to generate nanolayers of nanostructures of Zn4Sb3 with SiO2 as host and as buffer layer using a combination of co-deposition and MeV ion bombardment taking advantage of the electronics energy deposited in the MeV ion track due to ionization in order to nucleate nanostructures. The electrical and thermal properties of the layered structures were studied before and after bombardment by 5 MeV Si ions at various fluences to form nanostructures in layers of SiO2 containing Zn4Sb3. Rutherford Backscattering Spectrometry (RBS) was used to monitor the stoichiometry before and after MeV bombardments.
In this study the results of polychromatic X-ray microbeam analysis (PXM) of the structural changes caused by FIB in nitride heterostructures are presented and discussed in connection with micro-photoluminescence (μ-PL), fluorescent analysis, scanning electron (SEM) and transmission electron microscopy (TEM) data. It is shown that FIB processing distorts the lattice in the InGaN/GaN layer not only in the immediate vicinity of the processed area but also in the surroundings. A narrow amorphidized top layer is formed in the direct ion beam impact area.
In order to keep the stoichemistry of Bi2Te3 and Sb2Te3 so as to keep the electrical and thermal conductivity advantage of the layered structure of bulk Bi2Te3 and Sb2Te3 in each period of the superlattice, magnetron sputtering, which is operated at relatively low temperature, was used to deposit multiplayer Bi2Te3/Sb2Te3 thermoelectric superlattice device. The two guns in our magnetron sputtering device is oriented at a certain angle to get off-axis plasma plume, which will form lattice with preferential orientation for electrical conductivity in each layer. The super lattice was then bombarded by MeV Si ions with different fluence in order to form nanoscale cluster quantum dot-like structures. In addition to the effect of quantum well confinement of the phonon transmission, the nanoscale clusters produced by the bombardment of ion beam further adversely affect the thermal conductivity. The defect and disorder in the lattice caused by bombardment and the grain boundary of these nanoscale clusters increase the scattering of phonon and increase the chance of the inelastic interaction of phonon and the annihilation of phonon, this limits phonon mean free path. Phonons are chiefly absorbed and dissipated along the lattice, therefore reduces the cross plane thermal conductivity, The increases of the electron density of state in the miniband of nanoscale cluster quantum dot-like structure formed by bombardment also increases Seebeck coefficient, and the electrical conductivity. Eventually, the thermo-electric figure of merit of superlattice films increases.
In this work, Ultra High Molecular Weight Poly Ethylene (UHMWPE) samples were implanted with W + C ion by using Metal-Vapour Vacuum Arc (MEVVA) ion implantation technique. Samples were implanted with W and C atoms with a fluence of 1017ion/cm2 and extraction voltage of 30 kV. Mechanism underlies this modification characterized with ATR-FTIR, UV-VIS-NIR Spectrum and Rutherford Backscattering Spectrometry (RBS). Surface morphology of implanted and unimplanted samples were examined in nanoscale with AFM.
Semiconducting â-Zn4Sb3 and ZrNiSn-based half-heusler compound thin films were prepared by co-evaporation for the application of thermoelectric (TE) materials. High-purity solid zinc and antimony were evaporated by electron beam to grow the â-Zn4Sb3 thin film while high-purity zirconium powder and nickel tin powders were evaporated by electron beam to grow the ZrNiSn-based half-heusler compound thin film. Rutherford backscattering spectrometry (RBS) was used to analyze the composition of the thin films. The grown thin films were subjected to 5 MeV Si ions bombardments for generation of nanostructures in the films. We measured the thermal conductivity, Seebeck coefficient, and electrical conductivity of these two systems before and after 5 MeV Si ions beam bombardments. The two material systems have been identified as promising TE materials for the application of thermal-to-electrical energy conversion, but the efficiency still limits their applications. The electronic energy deposited due to ionization in the track of MeV ion beam can cause localized crystallization. The nanostructures produced by MeV ion beam can cause significant change in both the electrical and the thermal conductivity of thin films, thereby improving the efficiency. We used the 3ù-method measurement system to measure the cross-plane thermal conductivity ,the Van der Pauw measurement system to measure the cross-plane electrical conductivity, and the Seebeck-coefficient measurement system to measure the cross-plane Seebeck coefficient. The thermoelectric figures of merit of the two material systems were then derived by calculations using the measurement results. The MeV ion-beam bombardment was found to decrease the thermal conductivity of thin films and increase the efficiency of thermal-to-electrical energy conversion.
We have succeeded in the fabrication of low-resistivity p-type ZnS with blue -Ag emission by triple-codoping using Ag, a Zn-substituting species, In, a Zn-substituting species, and N, a S-substituting species. For the realization of blue-Ag emission at 436 nm, we use In species as co-activators with Ag activators. For the control of conduction type to obtain p-type ZnS thin films, we introduce N species as acceptors into ZnS codoped with the Ag and In. On the basis of the analysis of the experimental data and calculated results, we proposed a model for ZnS:(Ag, In, and N), in which some of the In species act as coactivators with Ag activators and other In species act as reactive codopants with N acceptors.